Optimal Transmission Range and Charging Time for Qi-Compliant Systems

Although widespread in the market, the wireless power transfer devices following the Qi Standard suffer from limited transmission range and link instability. Previous works often address these issues by proposing improvements for both transmitting and receiving sides, which disposes of the Qi interoperability and ease of purchasing. This article proposes an optimal transmitting-range-maximization algorithm for the receiving part of a Qi-compliant system. The algorithm actuates over the receiving circuit by dynamically adjusting its internal impedance. The proposed method obtains the optimal result in
$\Theta (1)$
time and does not require any direct information from the transmitting part neither any preparameterized data. Simulation results indicate that the proposed algorithm can mitigate the issue of re-establishing the link when the coils are loosely coupled.